Related by context. Frequent words. (Click for all words.) 83 circadian rhythms 74 circadian 74 circadian clock 64 biological clocks 63 metabolism 61 melatonin 60 wakefulness 59 metabolic 59 metabolic processes 56 serotonin 55 insulin secretion 53 leptin 52 Melatonin 52 REM sleep 51 glucose metabolism 51 metabolic pathways 50 homeostasis 50 sleep 50 physiological 50 protein synthesis 50 SIRT1 49 thyroid hormone 49 brain circuitry 49 mitochondria 49 hormonal 48 plasticity 48 sleepiness 48 signaling pathway 48 synaptic 48 cortisol 48 cortisol levels 48 molecular mechanism 48 menstrual cycle 47 signaling pathways 47 thyroid function 47 neurogenesis 47 neurones 47 neurodegeneration 47 blood glucose levels 47 GABA 46 neurotransmitters 46 neurotransmitter 46 daytime sleepiness 46 hormone 46 cognition 46 physiology 46 neurons 46 nerve cells 46 phosphorylation 46 endocrine 46 ghrelin 46 genes 45 cognitive functioning 45 stress hormones 45 seasonal affective disorder 45 dopamine 45 amino acid 45 hormones 45 sleep deprived 45 secretion 45 cognitive function 45 blood sugar 45 epigenetic 45 glutathione 45 mitochondrial 45 hypothalamus 45 insulin resistance 45 synapses 44 gut bacteria 44 protein 44 hypoxia 44 carbohydrate intake 44 alertness 44 oscillations 44 proteins 44 Dopamine 44 cognitive functions 44 kidney function 44 glutamate 44 gene expression 44 caffeine 44 menstrual cycles 44 methylation 44 enzyme 43 stress hormone cortisol 43 Hormones 43 calorie restriction 43 caloric intake 43 innate immune system 43 BDNF 43 ovulation 43 Serotonin 43 autophagy 43 Drosophila 43 adiponectin 43 levodopa 43 norepinephrine 43 molecular mechanisms 43 neurobiological 43 mammalian 43 physiologically